A cash register was part of the Internet of Things
long before there was an Internet of Things.
A cash register, or Point Of Sale (POS) system, is a device that contains an operating system and network connectivity. It performs a very specific task, sending data back to a central server. Put that way, it sounds very much like part of the Internet of Things (IoT).
The big difference between POS and “IoT” is that devices in the “new” Internet of Things tend to run some flavor of Linux, while many cash registers run some version of the Windows operating system. As such, these cash registers are susceptible to the millions of pieces of malware written for Windows.